From patchwork Thu Feb 29 10:43:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Huth X-Patchwork-Id: 13576951 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 23541C48BF6 for ; Thu, 29 Feb 2024 10:44:09 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rfdtJ-00025A-TA; Thu, 29 Feb 2024 05:43:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rfdtI-000251-Fl for qemu-devel@nongnu.org; Thu, 29 Feb 2024 05:43:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rfdtG-0002II-Au for qemu-devel@nongnu.org; Thu, 29 Feb 2024 05:43:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709203427; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=i63b46w1LySKhhFANiCq+HAyYOnafoHBsZu2zDiOK9s=; b=VUnJvNRewrrfkv4su76oPcYeIjnPXsqCn2AHLVGjkKW4+UjfBJHN1lZZ1z7vExULpAq7tv 811V50sws2hksLmchtDpeO25acMpZITLj+N4NJgYnKsrIY0WgCqG9g/s8xmfueCJOSTA57 s/fhlqA/tHoNCAUyorLgYjgjRYodBBQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-197-VLOgZqEGP4urXiIRRklBGQ-1; Thu, 29 Feb 2024 05:43:43 -0500 X-MC-Unique: VLOgZqEGP4urXiIRRklBGQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1C1BD29AC00F; Thu, 29 Feb 2024 10:43:43 +0000 (UTC) Received: from thuth-p1g4.redhat.com (unknown [10.39.192.171]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2DD941BDB1; Thu, 29 Feb 2024 10:43:40 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= Cc: Paolo Bonzini , Antoine Damhet , Charles Frey Subject: [PATCH] chardev/char-socket: Fix TLS io channels sending too much data to the backend Date: Thu, 29 Feb 2024 11:43:37 +0100 Message-ID: <20240229104339.42574-1-thuth@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.102, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Commit ffda5db65a ("io/channel-tls: fix handling of bigger read buffers") changed the behavior of the TLS io channels to schedule a second reading attempt if there is still incoming data pending. This caused a regression with backends like the sclpconsole that check in their read function that the sender does not try to write more bytes to it than the device can currently handle. The problem can be reproduced like this: 1) In one terminal, do this: mkdir qemu-pki cd qemu-pki openssl genrsa 2048 > ca-key.pem openssl req -new -x509 -nodes -days 365000 -key ca-key.pem -out ca-cert.pem # enter some dummy value for the cert openssl genrsa 2048 > server-key.pem openssl req -new -x509 -nodes -days 365000 -key server-key.pem \ -out server-cert.pem # enter some other dummy values for the cert gnutls-serv --echo --x509cafile ca-cert.pem --x509keyfile server-key.pem \ --x509certfile server-cert.pem -p 8338 2) In another terminal, do this: wget https://download.fedoraproject.org/pub/fedora-secondary/releases/39/Cloud/s390x/images/Fedora-Cloud-Base-39-1.5.s390x.qcow2 qemu-system-s390x -nographic -nodefaults \ -hda Fedora-Cloud-Base-39-1.5.s390x.qcow2 \ -object tls-creds-x509,id=tls0,endpoint=client,verify-peer=false,dir=$PWD/qemu-pki \ -chardev socket,id=tls_chardev,host=localhost,port=8338,tls-creds=tls0 \ -device sclpconsole,chardev=tls_chardev,id=tls_serial QEMU then aborts after a second or two with: qemu-system-s390x: ../hw/char/sclpconsole.c:73: chr_read: Assertion `size <= SIZE_BUFFER_VT220 - scon->iov_data_len' failed. Aborted (core dumped) It looks like the second read does not trigger the chr_can_read() function to be called before the second read, which should normally always be done before sending bytes to a character device to see how much it can handle, so the s->max_size in tcp_chr_read() still contains the old value from the previous read. Let's make sure that we use the up-to-date value by calling tcp_chr_read_poll() again here. Fixes: ffda5db65a ("io/channel-tls: fix handling of bigger read buffers") Buglink: https://issues.redhat.com/browse/RHEL-24614 Reviewed-by: Daniel P. Berrangé Signed-off-by: Thomas Huth Reviewed-by: Marc-André Lureau Reviewed-by: Antoine Damhet Tested-by: Antoine Damhet --- Sorry if you've got this mail twice - I forgot to CC: qemu-devel when I sent it out the first time ... *facepalm* chardev/char-socket.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/chardev/char-socket.c b/chardev/char-socket.c index 67e3334423..8a0406cc1e 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -496,9 +496,9 @@ static gboolean tcp_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque) s->max_size <= 0) { return TRUE; } - len = sizeof(buf); - if (len > s->max_size) { - len = s->max_size; + len = tcp_chr_read_poll(opaque); + if (len > sizeof(buf)) { + len = sizeof(buf); } size = tcp_chr_recv(chr, (void *)buf, len); if (size == 0 || (size == -1 && errno != EAGAIN)) {